// This file is part of Substrate.

// Copyright (C) Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.

//! Network event types. These are not the part of the protocol, but rather
//! events that happen on the network like DHT get/put results received.

use crate::types::ProtocolName;

use bytes::Bytes;

use sc_network_common::role::ObservedRole;
use sc_network_types::{
	kad::{Key, PeerRecord},
	multiaddr::Multiaddr,
	PeerId,
};

/// Events generated by DHT as a response to get_value and put_value requests.
#[derive(Debug, Clone)]
#[must_use]
pub enum DhtEvent {
	/// Found closest peers to the target `PeerId`. With libp2p also delivers a partial result
	/// in case the query timed out, because it can contain the target peer's address.
	ClosestPeersFound(PeerId, Vec<(PeerId, Vec<Multiaddr>)>),

	/// Closest peers to the target `PeerId` has not been found.
	ClosestPeersNotFound(PeerId),

	/// The value was found.
	ValueFound(PeerRecord),

	/// The requested record has not been found in the DHT.
	ValueNotFound(Key),

	/// The record has been successfully inserted into the DHT.
	ValuePut(Key),

	/// An error has occurred while putting a record into the DHT.
	ValuePutFailed(Key),

	/// Successfully started providing the given key.
	StartedProviding(Key),

	/// An error occured while registering as a content provider on the DHT.
	StartProvidingFailed(Key),

	/// The DHT received a put record request.
	PutRecordRequest(Key, Vec<u8>, Option<PeerId>, Option<std::time::Instant>),

	/// The providers for [`Key`] were found. Multiple such events can be generated per provider
	/// discovery request.
	ProvidersFound(Key, Vec<PeerId>),

	/// `GET_PROVIDERS` query finished and won't yield any more providers.
	NoMoreProviders(Key),

	/// `GET_PROVIDERS` query failed and no providers for [`Key`] were found. libp2p also emits
	/// this event after already yielding some results via [`DhtEvent::ProvidersFound`].
	ProvidersNotFound(Key),
}

/// Type for events generated by networking layer.
#[derive(Debug, Clone)]
#[must_use]
pub enum Event {
	/// Event generated by a DHT.
	Dht(DhtEvent),

	/// Opened a substream with the given node with the given notifications protocol.
	///
	/// The protocol is always one of the notification protocols that have been registered.
	NotificationStreamOpened {
		/// Node we opened the substream with.
		remote: PeerId,
		/// The concerned protocol. Each protocol uses a different substream.
		/// This is always equal to the value of
		/// `sc_network::config::NonDefaultSetConfig::notifications_protocol` of one of the
		/// configured sets.
		protocol: ProtocolName,
		/// If the negotiation didn't use the main name of the protocol (the one in
		/// `notifications_protocol`), then this field contains which name has actually been
		/// used.
		/// Always contains a value equal to the value in
		/// `sc_network::config::NonDefaultSetConfig::fallback_names`.
		negotiated_fallback: Option<ProtocolName>,
		/// Role of the remote.
		role: ObservedRole,
		/// Received handshake.
		received_handshake: Vec<u8>,
	},

	/// Closed a substream with the given node. Always matches a corresponding previous
	/// `NotificationStreamOpened` message.
	NotificationStreamClosed {
		/// Node we closed the substream with.
		remote: PeerId,
		/// The concerned protocol. Each protocol uses a different substream.
		protocol: ProtocolName,
	},

	/// Received one or more messages from the given node using the given protocol.
	NotificationsReceived {
		/// Node we received the message from.
		remote: PeerId,
		/// Concerned protocol and associated message.
		messages: Vec<(ProtocolName, Bytes)>,
	},
}
